检索结果-内蒙古大学图书馆

International Conference on Renewable power generation, RPG 2015

作者： Li, Kangping Wang, Fei Zhen, Zhao Sun, Yujing Mi, Zengqiang Sun, Hongbin Liu, Chun Wang, Bo Lu, Jing State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Baoding Hebei Province071003 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Haidian District Beijing100084 China China Electric Power Research Institute Haidian District Beijing100192 China

ISBN: (纸本)9781785610400

Operating Statuses Identification (OSI) can help operators to find fault timely and minimize the loss. So it is of great significance for optimal operation of photovoltaic (PV) plants. The loss quantity of electricity (LQOE) is defined as that should have been generated but actually not, which is caused by inverter fault, PV modules fault, dust stratification or combinations of them. Firstly, mathematical models of PV cells are proposed to figure out the LQOE of each PV module. Secondly, after analysing the relation between LQOE and operating statuses, an index set of LQOE describing the distinction of different operating statuses are defined including four statistical feature parameters and a user-defined index. Thirdly, Support Vector Classification models for OSI (OSI-SVC) are built with input features extracted from the index set. Lastly, simulations are carried out to verify the effectiveness and evaluate the performance of the OSI-SVC models. The results indicated that the operating statuses can be effectively recognized by the proposed model.

关键词： Support vector machines

来源：评论

学校读者我要写书评

暂无评论

Cloud identification model for sky images based on Otsu

Cloud identification model for sky images based on Otsu

引用

International Conference on Renewable power generation, RPG 2015

作者： Li, Hongping Wang, Fei Ren, Hui Sun, Hongbin Liu, Chun Wang, Bo Lu, Jing Zhen, Zhao State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Baoding Hebei Province071003 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Haidian District Beijing100084 China China Electric Power Research Institute Haidian District Beijing100192 China

ISBN: (纸本)9781785610400

Irradiance changes caused by clouds movement are the mam factors, which lead to mutation of photovoltaic power. In order to increase the accuracy of the ultra-short-term photovoltaic power prediction, based on of clouds images, the cloud identification for sky images is one of the primary aspects for improving photovoltaic power accuracy. A cloud identification model for sky images is established based on Otsu. Firstly, a series of sky images are collected by Total Sky Imager (TSI) with the regions of clouds and sky are distinguished. Secondly, the color features (based on RGB values) of pixels in sample images and the spectral and texture features of the whole image are extracted;Finally, we established a cloud identification model for sky images based on Otsu according to the clouds' and sky areas' division and the general characteristics featured by pixels and images. The simulated results show that the model in this paper can identify the clouds in a sky images effectively.

关键词： Pixels

来源：评论

学校读者我要写书评

暂无评论

Fault Line Identification of Single Line to Ground Fault for Non-Effectively Grounded Distribution Networks with Double-Circuit Lines

Fault Line Identification of Single Line to Ground Fault for...

引用

IEEE power and Energy Society General Meeting

作者： Bo Jiang Xinzhou Dong Shenxing Shi Bin Wang State Key Lab. Of Control and Simulation of Power System and Generation Equipment Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781467380416

Single Line to Ground (SLG) faults in non-effectively grounded networks are difficult to detect. Immune to neutral point grounding type, load conditions and system operation conditions, traveling-wave based method is an effective fault line identification method. However, due to the strong coupling between the double-circuit lines, the wavefront magnitude of them are the same, and the polarity of them are opposite. Thus, the mal-identification will be resulted under such condition. This paper analyzed the traveling wave characteristics of double-circuit lines, and proposed an improved fault line identification method based on the initial process of zero sequence currents and voltage traveling waves. Tests show that, the proposed method has high effectiveness in fault line identification of double-circuit lines in distribution networks.

关键词： distribution networks double-circuit fault line identification non-effectively grounded traveling wave Double circuit power grids line down Earth faults traveling waves single line

来源：评论

学校读者我要写书评

暂无评论

Dynamic Response of Rubbing Happening in a Flexible Rotor-Bearing system

Dynamic Response of Rubbing Happening in a Flexible Rotor-Be...

引用

2015 International Conference on Electrical, Automation and Mechanical Engineering(EAME 2015)

作者： J.M.Chen D.X.Jiang T.T.Deng J.S.Wang J.L.Zhong S.B.Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Guizhou Electric Power Research Institute

ISBN: (纸本)9781510806528

To reduce the steam loss and raise the efficiency of the steam turbine,the vapour seals are applied in the inner cylinder of the steam *** small gap may easily results in the rubbing happening in the inner ***,the rotor is a flexible *** this paper,dynamic response of rubbing happening in a flexible rotor-bearing system was studied.A simplified flexible rotor-bearing system was constructed,whose rotating speed was between the 1st and 2nd critical rotating *** effect was considered in the analysis,*** rubbing introduce heat and result in the thermally induced *** transient thermal bow was treated as a pair of moments functioning on the shaft segment where rubbing *** shows the amplitude and phase of vibration would be stable after a long *** severity of rubbing affect the stabilization time,which could be regarded as a diagnostic feature to identify the severity of rub happening in a flexible rotor-bearing system.

关键词： thermally induced vibration equivalent thermal moment stabilization time rubbing flexible rotor-bearing system

来源：评论

学校读者我要写书评

暂无评论

Ambient signal based load model parameter identification using optimization method

Ambient signal based load model parameter identification usi...

引用

IEEE General Meeting power& Energy Society

作者： Xinran Zhang Chao Lu Yingduo Han Songtai Yu Jifeng Wang He Huang Yinsheng Su State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China China Southern Power Grid Guangzhou China

Load modelling is a crucial part in modelling a power system. The complex, nonlinear and stochastic characteristics of power load increase the difficulty of modelling. In this paper, a new approach of ambient signal based load model parameter identification method is proposed to solve this problem. With the proposed method, load model parameter can be identified in any time regardless of the existence of fault. First, Z+M model is simplified to reduce the number of parameters to be identified. Then, parameters of Z+M model are identified with an optimization method, the objective function of which is calculated from WAMS measured power and voltage data. An iterative process is proposed to solve the problem of initial value sensitivity in optimization problems. Finally, the effectiveness of this identification method is validated through the simulation results on WSCC three machines nine nodes system under different operation situation including both small disturbance and large disturbance.

关键词： Load modeling Optimization Integrated circuit modeling Parameter estimation Data models Reactive power power measurement

来源：评论

学校读者我要写书评

暂无评论

A real-time wind power control method for power systems with high wind power penetration and its implementation

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2015年第21期39卷 23-29页

作者： Wang, Bin Sun, Yong Wu, Wenchuan Zheng, Taiyi Zhang, Boming State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China Department of Electrical Engineering Tsinghua University Beijing100084 China State Grid Jilin Electric Power Supply Company Changchun130021 China

A real-time wind power control method is proposed to accommodate the severe fluctuation of wind power, which can be used in power systems with high wind power penetration. The maximum allowable wind power generation is estimated online according to the automatic generation control (AGC) downward spinning reserve and the tie-line power deviation. Considering the different priorities for wind farms and the transmission security constraints, different control strategies, such as corrective control to eliminate the transmission congestion, optimal dispatch considering the trade-off between minimum curtailment of wind power and the fairness among wind farms, are integrated in the proposed method. The numerical simulation on the test system and the results of field operation in a provincial power grid show that the method is efficient and practical. © 2015 Automation of Electric power systems Press.

关键词： Wind farm

来源：评论

学校读者我要写书评

暂无评论

Natural Frequency and Dynamic Response of Rotor system of Steam Turbine Modelled with Euler-Bernoulli Beam

Natural Frequency and Dynamic Response of Rotor System of St...

引用

2015 International power,Electronics and Materials Engineering Conference(IPEMEC 2015)

作者： T.T.Deng J.S.Wang X.J.Li J.L.Zhong S.B.Wang S.P.An W.G.Yang D.X.Jiang Guizhou Electric Power Test and Research Institute State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal EngineeringTsinghua University

ISBN: (纸本)9781510806474

Based on Finite element method(FEM),analysis of natural frequency and dynamics response is carried out in this ***,modeling of rotor system in steam turbines is analyzed with Euler-Bernoulli beam ***,natural frequency of the rotor system is obtained and ***,dynamic response of the rotor system is simulated and the vibration of the rotor system is *** results show that the proposed model can obtain results with high accuracy,and the model is *** modeling approach presented in this work provides a fast and accurate method in analyzing dynamic characteristics of the practical rotor system in steam turbine units

关键词： Natural frequency transient response rotor system steam turbine Euler-Bernoulli Beam

来源：评论

学校读者我要写书评

暂无评论

Quasi-Uniform Magnetic Field Generated by Multiple Transmitters of Magnetically-Coupled Resonant Wireless power Transfer

Quasi-Uniform Magnetic Field Generated by Multiple Transmitt...

引用

International Conference on Electrical Machines and systems

作者： Yiming Zhang Ting Lu Zhengming Zhao Fanbo He Kainan Chen Liqiang Yuan State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781479988068

Magnetically-coupled resonant wireless power transfer (MCR-WPT) has been a research focus in recent years. Multiple transmitters are employed to improve efficiency in a wide area. In this paper, the MCR-WPT system with two transmitters supplied by the same source is modeled and its equivalent circuit is depicted. The mutual inductance between the two transmitters is considered. Proper connection of the transmitters results in the enhancement of the magnetic field in certain areas. Based on the circuit theory, the explicit expression of the efficiency is derived. The quasi-uniform magnetic field and roughly equal efficiency are analyzed.

关键词： magnetic resonance multiple transmitters uniform magnetic field wireless power transfer

来源：评论

学校读者我要写书评

暂无评论

Ordinal optimization theory based planning for clustered wind farms considering the capacity credit

Ordinal optimization theory based planning for clustered win...

引用

第13届全国博士生学术年会——新能源专题

作者： Yi Wang Chongqing Kang Ning Zhang Qianyao Xu Rui Shi Hui Li Jinyu Xiao Zhidong Wang Shuai Wang State Key Lab of Control and Simulation of Power Systems and Generation Equipment (Department of Ele State Power Economic Research Institute ChangpingDistrictBeijing 102209China

Wind power planning aims at optimally locating and sizing wind ***,it tends to choose the wind farms with the richest wind resource in order to maximize the energy ***, the capacity benefit of wind power should also be considered in the large-scale clustered wind farm planning since the correlation among the wind farms performs an obvious influence on the capacity benefit brought by the whole wind *** paper proposes a planning model considering both energy and capacity benefit of the wind ***, the capacity benefit is evaluated by wind power capacity *** Ordinal Optimization (OO) theory, capable of handling problems with non-analytical forms, is applied to address the *** verify its feasibility and advantages, the proposed model is compared with widely-used genetic algorithm (GA) via a modified IEEE RTS-79 system and a real world case of Ningxia, *** results show that the diversity of wind farm enhances the capacity credit of wind power.

关键词： Capacity credit Correlation Ordinal Optimization Planning Wind power

来源：评论

学校读者我要写书评

暂无评论

A hybrid converter for energy management of EV drives

A hybrid converter for energy management of EV drives

引用

Annual IEEE Conference on Applied power Electronics Conference and Exposition (APEC)

作者： Teng Hu Lie Xu Lin Qiu Yongdong Li Xuejun Han Department of Electrical Engineering Northeast Dianli University Jilin China State Key Lab. of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

This paper proposed a novel hybrid power converter topology based on cascaded H-bridge (CHB) and matrix converter (MC) in order to improve the performance of the conventional energy management systems in EV/PHEV application. The power demand by the load is supplied by the generator and batteries, which are connected to the primary winding of the medium frequency transformer (MFT) by the matrix converter and the cascaded H-bridge respectively. The power transfer between the sources and load can be controlled and isolated by using the MFT. The cascaded H-bridge, as the energy control unit, can be used to balance the voltage/SOC of battery packages individually, significantly improve the modularity, stability and safety of EV system.

关键词： Batteries Matrix converters Energy management system-on-chip Topology Voltage control Windings

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：